Switch Settings

                               PC Switch Settings  (includes PC-1 and PC-2)
                               XT Switch Settings
                               AT Switch Settings

                               EGA Switch Settings

 DIP switches on the PC and XT tell the BIOS what equipment and how much
 memory is installed.  These switches are read during the POST and bit
 flags are set into the BIOS Equipment List variable and are made available
 to the programmer via INT 11H (Equipment Check).

 The topics above show details of the DIP switch settings, as well as
 jumpers and other hardware configuration for the different standard IBM
 models.

 Non-IBM PCs usually don't adhere to these settings.  For instance, Compaq
 Portable switches bear no resemblance to those of the standard PC and
 aren't documented in any manual available to Compaq owners.  Deskpro
 switches are labeled inside the chassis.

See Also: POST
          Cables and Pin Outs
          INT 11H (get equipment list)
          INT 15H (extended AT services)
          BIOS Data Area
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